Aqueous binders for granular and/or fibrous substrates

Abstract

This invention relates to an aqueous binder composition containing a) at least one polymer P and b) at least one saccharide compound S, such that an amount of the saccharide compound S is ≧10 and ≦400 parts by weight per 100 parts by weight of polymer P, wherein an amount of an additional formaldehyde-containing binder is ≦50 parts by weight per 100 parts by weight of the summed overall amounts of the polymer P and the saccharide compound S. This invention also relates to a process for producing a shaped articles from granular and/or fibrous substrates where an aqueous binder composition of the present invention is applied to the granular and/or fibrous substrate, the granular and/or fibrous substrate thus treated is optionally shaped and then the granular and/or fibrous substrate thus obtained is thermally treated. This invention also relates to shaped articles obtained by a process of the present invention.

We claim: 
     
       1. An aqueous binder composition, comprising:
 a) at least one polymer P comprising in polymerized form
 ≧0.1 and ≦15 wt % of at least one acid-functional ethylenically unsaturated monomer, at least one α,β-monoethylenically unsaturated C 3  to C 6  mono- or dicarboxamide, or both (monomers A), 
 ≧8.0 and ≦30 wt % of at least one ethylenically unsaturated carboxylic acid nitrile or dinitrile (monomers B), 
 ≧0 and ≦5.0 wt % of at least one crosslinking monomer having two or more nonconjugated ethylenically unsaturated groups (monomers C), 
 ≧0 and ≦10 wt % of at least one monoethylenically unsaturated silane compound (monomers D), 
 ≧20 and ≦70 wt % of at least one ethylenically unsaturated monomer whose homopolymer has a glass transition temperature ≦30° C. (monomers E) and which differs from the monomers A to D, and 
 ≧25 and ≦71.9 wt % of at least one ethylenically unsaturated monomer whose homopolymer has a glass transition temperature ≧50° C. (monomers F) and which differs from the monomers A to D, 
 
 
       in polymerized form, wherein the amounts of monomers A to F sum to 100 wt %; and
 b) at least one saccharide compound S, an amount of which is ≧10 and ≦400 parts by weight per 100 parts by weight of the polymer P, 
 wherein: 
 an overall amount of additional formaldehyde-containing binder components is <50 parts by weight per 100 parts by weight of a sum of the polymer P and the saccharide compound S; and 
 conjugated aliphatic C 4  to C 9  diene compounds are excluded. 
 
     
     
       2. The aqueous binder composition according to  claim 1 , wherein:
 the at least one monomer E is selected from the group consisting of an ester of vinyl alcohol and a C 1  to C 10  monocarboxylic acid, a C 1  to C 10  alkyl acrylate, a C 5  to C 10  alkyl methacrylate, a C 5  to C 10  cycloalkyl acrylate, a C 5  to C 10  cycloalkyl methacrylate, a C 1  to C 10  dialkyl maleinate, a C 1  to C 10  dialkyl fumarate, and a mixture of at least two thereof; and 
 the at least one monomer F is selected from the group consisting of a vinylaromatic monomer, a C 1  to C 4  alkyl methacrylate, and a mixture thereof. 
 
     
     
       3. The aqueous binder composition according to  claim 1 , wherein the polymer P is in the form of an aqueous polymer dispersion. 
     
     
       4. The aqueous binder composition according to  claim 3 , wherein polymer particles of the aqueous polymer dispersion have a number average particle diameter of ≧50 and ≦400 nm. 
     
     
       5. The aqueous binder composition according to  claim 1 , wherein the polymer P comprises in polymerized form
 ≧0.5 and ≦10 wt % of at least one monomer A, 
 ≧10 and ≦25 wt % of at least one monomer B, 
 ≧0 and ≦1.5 wt % of at least one monomer C, 
 ≧0 and ≦5.0 wt % of at least one monomer D, 
 ≧25 and ≦65 wt % of at least one monomer E, and 
 ≧25 and ≦64.5 wt % of at least one monomer F. 
 
     
     
       6. The aqueous binder composition according to  claim 1 , wherein the polymer P comprises in polymerized form
 ≧3.0 and ≦8.5 wt % of acrylic acid, methacrylic acid, itaconic acid, acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, or a mixture of at least two thereof, 
 ≧10 and ≦20 wt % of acrylonitrile, methacrylonitrile, or a mixture thereof, 
 ≧0 and ≦1.5 wt % of 1,4-butylene glycol diacrylate, allyl methacrylate, divinylbenzene, or a mixture of at least two thereof, 
 ≧30 and ≦60 wt % of 2-ethylhexyl acrylate, n-butyl acrylate, ethyl acrylate, or a mixture of at least two thereof, and 
 ≧25 and ≦57 wt % of methyl methacrylate, styrene, tert-butyl methacrylate, or a mixture of at least two thereof. 
 
     
     
       7. The aqueous binder composition according to  claim 1 , wherein the polymer P comprises the monomers A, B, D, E and F and has a glass transition temperature of ≧15 and ≦45° C. 
     
     
       8. The aqueous binder composition according to  claim 1 , wherein the at least one saccharide compound S is selected from the group consisting of starch, cellulose, guaran, xanthan, alginate, pectin, chitosan, gum arabic gellan, and a mixture of at least two thereof. 
     
     
       9. The aqueous binder composition according to  claim 1 , wherein the at least one saccharide compound S is selected from the group consisting of a starch, a starch derivative, a starch substitution product, and a mixture of at least two thereof. 
     
     
       10. The aqueous binder composition according to  claim 1 , wherein the saccharide compound S has a weight average molecular weight of ≧50 000 and ≦1 000 000 g/mol. 
     
     
       11. The aqueous binder composition according to  claim 1 , comprising ≧40 and ≦250 parts by weight of the saccharide compound S per 100 parts by weight of the polymer P. 
     
     
       12. The aqueous binder composition according to  claim 1 , comprising ≦10 parts by weight of the additional formaldehyde-containing binder components per 100 parts of the sum of the polymer P and the saccharide compound S. 
     
     
       13. A binder for granular and/or fibrous substrates, comprising the aqueous binder composition of  claim 1 . 
     
     
       14. A process for producing a shaped article from granular and/or fibrous substrates, the process comprising:
 applying the aqueous binder composition of  claim 1  to a granular substrate, a fibrous substrate, or a mixture of both, to form a treated substrate; 
 optionally shaping the treated substrate; and 
 thermally treating the treated substrate at a temperature of ≧110° C. 
 
     
     
       15. The process of  claim 14 , wherein ≧1 and ≦100 g of a sum of the polymer P and the polysaccharide compound S are applied per 100 g of the granular substrate, the fibrous substrate, or a mixture of both. 
     
     
       16. A shaped article obtained by the process of  claim 14 . 
     
     
       17. The shaped article according to  claim 16 , which is adapted to produce a bituminized roofing membrane. 
     
     
       18. A bituminized roofing membrane, comprising the shaped article according to  claim 16 .